The mobile communication technologies can be described as developing every day, especially since the advent of the third generation mobile communication technology (3G), there is a new service after another. From the birth of the wireless terminal, the short message service (SMS), as one of the wireless terminal's basic functions, has always been one of the services most frequently used by the large number of mobile communication equipment owners.
However, when a user uses the short message service, he/she often encounters the following situation, that is, the user A sends a short message to the user B, but the user B might fail to reply a short message in time to the user A for the reasons such as that the user B is suspended, is powered off, or has no network signal, and the user A wants to obtain the current state of the user B automatically. At this time, it needs the network side to automatically feed back the current state of the user B to the user A.
In the existing SMS technology, one successful process of SMS sending and receiving is specifically as follows:
the mobile-services switching center (MSC) receives a Transfer Protocol Data Unit (TPDU) from the MS (Mobile Station) A, and queries the Visitor Location Register (VLR) for the mobile subscriber Integrated Services Digital Network (MSISDN) number corresponding to the MSA, and inserts the number into the protocol data unit (PDU) and then transmits the number to the Internetworking MSC for SMS (SMS-IWMSC). The MSC returns a report back to the MS according to the processing result. The SMS-IWMSC receives the TPDU that is from the MSA from the MSC, and checks the legitimacy of the SC address as the TPDU transmission destination, and then transmits the TPDU to the SC (Service Centre). The SMS-IWMSC returns a report to the MSC according to the processing result.
After the SC receives the TPDU, the Gateway MSC for SMS (SMS-GMSC) receives the TPDU from the SC and performs the parameter checking, and requires the HLR to perform the service authentication and inquiries the MSA for routing information, after the status is normal, routes the PDU to the MSC. The SMS-GMSC returns a report to the SC according to the processing result. After the MSC receives the TPDU from the SMS-GMSC, it queries the VLR of the MSB information, such as the location area information, and transmits the SMS to the MSB according to the query result. Moreover, the MSC returns a report back to the SMS-GMSC according to the processing result.
Therefore, after the SC successfully forwards the information sent by the MSA, it sends a status report to the MSA to inform the terminal that the short message has been forwarded successfully. However, after the SC forwards the message, information such as whether the message successfully reaches the MSB, and what the current state of the MSB is if the MSB did not respond the information is not fed back to the MSA by the network side. Therefore, it is necessary to study a method for feeding back the current state of the receiving end of the message.